Effect of Current Polarity on Tribological Behavior of Copper-Aluminum Electrical Interface

Wear and friction in sliding electrical contacts is affected by a multitude of factors such as contact load, current density, sliding speed, sliding distance and materials in contact [1], [2]. Very limited studies have been done to investigate the effect of current polarity on wear and coefficient of friction. In the present study, the authors investigate the effect of current polarity on the frictional response and wear of copper-aluminum interface. Copper wire mounted on a fixture is slid on aluminum flat under different current levels. Large scale melting at the interface was observed when slider (copper) was maintained as anode. Observations of the slider and flat surface made under microscope reveal material transfer of aluminum on copper even at low current levels of 60 Amperes. The results of the study can be used in the light of applying different coatings or surface design for anode and cathode in order to minimize their wear or degradation.

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Effect of Applied Pressure on the Electrical Resistance of Carbon Nanotube Fibers

Materials ◽

10.3390/ma14092106 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2106

Author(s):

Chris J. Barnett ◽

James D. McGettrick ◽

Varun Shenoy Gangoli ◽

Ewa Kazimierska ◽

Alvin Orbaek White ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Electrical Resistance ◽

Copper Wire ◽

Applied Pressure ◽

Radial Strain ◽

Electrical Current ◽

Electrical Contacts ◽

Electrical Performance ◽

Macro Scale ◽

Carbon Nanotube Fibers

Carbon nanotubes (CNTs) can be spun into fibers as potential lightweight replacements for copper in electrical current transmission since lightweight CNT fibers weigh <1/6th that of an equivalently dimensioned copper wire. Experimentally, it has been shown that the electrical resistance of CNT fibers increases with longitudinal strain; however, although fibers may be under radial strain when they are compressed during crimping at contacts for use in electrical current transport, there has been no study of this relationship. Herein, we apply radial stress at the contact to a CNT fiber on both the nano- and macro-scale and measure the changes in fiber and contact resistance. We observed an increase in resistance with increasing pressure on the nanoscale as well as initially on the macro scale, which we attribute to the decreasing of axial CNT…CNT contacts. On the macro scale, the resistance then decreases with increased pressure, which we attribute to improved radial contact due to the closing of voids within the fiber bundle. X-ray photoelectron spectroscopy (XPS) and UV photoelectron spectroscopy (UPS) show that applied pressure on the fiber can damage the π–π bonding, which could also contribute to the increased resistance. As such, care must be taken when applying radial strain on CNT fibers in applications, including crimping for electrical contacts, lest they operate in an unfavorable regime with worse electrical performance.

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Surface Design for Precise Control of Spatial Growth of a Mesostructured Inorganic/Organic Film on a Large-Scale Area

Langmuir ◽

10.1021/la061405l ◽

2007 ◽

Vol 23 (6) ◽

pp. 3265-3272 ◽

Cited By ~ 19

Author(s):

Atsushi Hozumi ◽

Satoshi Kojima ◽

Shusaku Nagano ◽

Takahiro Seki ◽

Naoto Shirahata ◽

...

Keyword(s):

Large Scale ◽

Organic Film ◽

Surface Design ◽

Precise Control ◽

Spatial Growth

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Analysis of the effects of induced fields from sliding electrical contacts

2004 12th Symposium on Electromagnetic Launch Technology, 2004. ◽

10.1109/elt.2004.1398059 ◽

2005 ◽

Author(s):

V. Thiagarajan

Keyword(s):

Electrical Contacts ◽

Sliding Electrical Contacts

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Sliding Electrical Contacts

Electrical Contacts ◽

10.1201/b15640-25 ◽

2013 ◽

pp. 1039-1039

Keyword(s):

Electrical Contacts ◽

Sliding Electrical Contacts

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Analysis of the effects of induced fields from sliding electrical contacts

IEEE Transactions on Magnetics ◽

10.1109/tmag.2004.838750 ◽

2005 ◽

Vol 41 (1) ◽

pp. 241-245

Author(s):

V. Thiagarajan

Keyword(s):

Electrical Contacts ◽

Sliding Electrical Contacts

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Reliability Evaluation of Cu-Al WB in High Temperature and High Current Applications

10.1115/ipack2021-75890 ◽

2021 ◽

Author(s):

Pradeep Lall ◽

Sungmo Jung

Keyword(s):

High Temperature ◽

High Reliability ◽

Copper Wire ◽

Planck Equation ◽

Operating Conditions ◽

Polarization Curves ◽

Automotive Electronics ◽

Wire Bonds ◽

Chlorine Ions ◽

Copper Aluminum

Abstract High reliability harsh environment applications necessitate a better understanding of the acceleration factors under operating stresses. Automotive electronics has transitioned to the use of copper wire for first level interconnects. A number of copper wire formulations have emerged including palladium coated copper and gold-flash palladium coated copper. The corrosion reliability of copper wire bonds in high temperature conditions is not yet fully understood. The EMC used to encapsulate chips and interconnects can vary widely in formulation, including pH, porosity, diffusion rate, composition of contaminants and contaminant concentration. To realistically represent the expected wirebond reliability, there is need for a predictive model that can account for environmental conditions, operating conditions, and exposure to EMCs. In this paper, different EMCs were studied in a high-temperature-current environment with temperature range of 60°C–100°C under current of 0.2A–1A. The diffusion kinetics based on the Nernst-Planck Equation for migration of the chlorine ions has been coupled with the Butler-Volmer equation for corrosion kinetics to create a Multiphysics model. Polarization curves have been measured for copper, aluminum and intermetallics under a number of pH values, and chlorine-ion concentrations. Tafel parameters have been extracted through measurements of the polarization curves.

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